One day, Kouzai Haruma woke up in an empty room. With more than a dozen men and women dressed only in kantou gowns. Soon after, a man appeared to guide them, but he did not know why or how they had been brought there. From there, we were led to a town centered around a dungeon. Those who came here were obliged to either become “Explorers” and conquer the dungeon or become “Supporters” and assist the “Explorers”. In addition, they are first given a skill, which greatly affects their subsequent activities, and the skill Haruma obtained was the “Angel Summon” skill. When he used that skill, he was met by an angel who called herself Sera. Sera said she could summon items at random for a price. ――Can you make make Sera feel good ……? The price the angel asked for was pleasure. Moreover, the rarity of the item summoned changes according to the degree of pleasure given by s*x. ――In other words, I’m going to make the angel c*m and spin the gacha! …… What a wonderful system. After having s*x with Sera for the duration of the preparation period, Haruma begins exploring the dungeon, making use of rare items and the abilities enhanced by them. As he explores the dungeon solo, Haruma soon meets and has relationships with various women. He also discovers that the s*x he has with these female explorers is also reflected in the rarity of the items he summons, and so he builds a harem. While enjoying his harem life with angels and female explorers and exploring the dungeon, one day Haruma is reunited with a childhood friend who was newly sent to this place. She knew about Haruma’s condition before coming here. Hearing this, Haruma is forced to solve the mystery of why he was sent here and what this dungeon is for.